This invention relates generally to processes and apparatus for crimping contact pieces to electrical leads and is more particularly concerned with such apparatus and processes in which leads are inserted between U formed, upwardly-extending, crimping claws of such contact pieces on a base frame while a rammer, with crimpers thereon, interact with the base frame to bend the crimping claws tightly about the leads. The invention concerns such apparatus and processes in which individual contact pieces are connected in series to form a band which is arranged and transported along the base frame in a forward transporting direction with a finger which engages the band and with a holding element which holds the band to prevent rearward, or motion opposite to the forward transport direction, transport thereof.
In well known processes the moving of electrical leads between upwardly extending crimping claws of contact pieces is difficult because arrangements of the leads to the upwardly extending crimping claws of the contact pieces is not sufficiently exact. The contact pieces, with their U-formed upwardly extending crimping claws, are shoved onto ends of leads without the lead ends being exactly positioned relative to the crimping claws. Because of this, individual strands of stranded wire forming lead ends sometimes strike the contact pieces when they are shoved therein so that they are not gripped by the crimping claws when they are bent. It is therefore a purpose of this invention to improve this prior art process such that lead ends, which are to be crimped to contact pieces, are more exactly arranged relative to the upwardly extending crimping claws and, in addition, are not moved between the claws, end first.
Also, by well known apparatus of the art of this invention a band of series connected contact pieces is transported in the forward direction by a lever-like finger whose angled free end is pressed by means of a spring on the band of series connected contact pieces. When the finger is transported in the forward direction, the angled, or bent, free end engages an edge of the contact pieces and shoves these in the forward transporting direction toward a crimping, or striking, stamp. Because the connection between the transporting finger and the contact pieces is only keyed to one side, and because the shoving of the finger is accomplished with great acceleration, a brake must be provided to prevent the contact pieces from being thrown beyond a desired position. This brake is often a plate pressed against the contact pieces by spring force from above. Because of the large acceleration force, a pressing force of the braking plate must be great and with pressure susceptible contact pieces there is often the danger that this force will deform the contact pieces. The pressing force of the braking plate must also be great because when the finger travels rearwardly, its backside is pulled, and lifted across, the contact pieces in order to grip the next contact piece. This opposite driving against an edge to lift the finger is accomplished at a high velocity which introduces a rearward shoving force which must be braked. Therefore, it is an object of this invention to provide a transporting arrangement that catches the momentum of contact pieces at the end of a transporting stroke and in which the transporting, or shoving finger, when traveling rearwardly, produces no rearward shoving force on the contact pieces.